JP2005333922A - Method for retaining freshness of fish and shellfish - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for retaining freshness of fish and shellfish for a long time through keeping acid electrolytic water ice for a long time at the time of cold-storing fish and shellfish in acid electrolytic water ice. <P>SOLUTION: This method for retaining freshness of fish and shellfish comprises making ice while connecting one end of the secondary terminal of a high electric field generator 8 to a freezing tank 1 and giving high voltage electric field to acid electrolytic water when making ice with a brine freezing device from the acid electrolytic water obtained by electroanalyzing deep ocean water. Furthermore, the method comprises preserving fish and shellfish in the acid electrolytic water ice thus obtained, and retaining freshness of fish and shellfish for a long time owing to bacteria avoiding effect and sterilization effect which the acid electrolytic water ice has. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for preserving seafood and the like using ice obtained by making acidic electrolyzed water of salt water, and in particular, using acidic electrolyzed water ice made by applying a high voltage electric field to acidic electrolyzed water. The present invention relates to a method for preserving seafood and the like.

  Fresh food such as seafood and vegetables and fresh ingredients (hereinafter referred to as “fresh food”) are used for the growth of bacteria attached to the surface and direct contact with human hands during the distribution process until they reach the consumer. It is contaminated by newly attached bacteria. In order to prevent such bacterial growth and contamination by new bacteria, the freshness and quality of the food are kept by cooling with ice during transport, storage and display of fresh food. For example, in Patent Document 1, fresh food is kept cold with ice obtained by making electrolytic water generated by electrolyzing saline, reducing the number of bacteria attached to the surface of fresh food, bacteria and viruses from the outside, etc. It is described that the deterioration of fresh foods is prevented by preventing secondary contamination due to.

  In Patent Document 2, sterilization and maintenance of freshness of fresh food can be obtained by storing fresh food with ice made from seawater, especially deep seawater electrolyzed water (acidic water, alkaline water and mixed water thereof). It is described. Furthermore, Patent Document 3 discloses electrolyzed water ice in which electrolyzed water having a sodium ion concentration of 200 ppm or less, a pH of 4.5 to 6.8, and a hydrogen chloride concentration of 0.01 to 21% is frozen under cooling conditions of −40 ° C. or less. It is described that the effect of bactericidal power lasts for a long time when perishable foods are stored.

  From these Patent Documents 1 to 3, it is known that electrolyzed water ice of saline is suitable for preservation of fresh food and the like. In particular, the acidic water ice keeps the bacteria from growing by refrigeration, and at the same time, the bacteria attached to the surface and the bacteria due to secondary contamination can be sterilized by the sterilizing action of the acidic water generated by thawing, so that bacteria are easily attached. Most suitable as storage ice for seafood. Various ice making apparatuses have been put into practical use. When producing the electrolyzed water ice in large quantities, for example, a brine refrigeration method in which ice is made by cooling with a refrigerant such as calcium chloride or an alcohol solution, or an air blast refrigeration method in which ice is made by cooling with cold air are suitable.

  In Patent Literature 4, in the brine freezing method in which the frozen food is immersed and frozen in the antifreeze liquid, by shortening the time to pass through the maximum ice crystal formation zone (−1 to −5 ° C.) of the frozen food, In order to prevent water in the food tissue from growing into ice crystals and causing tissue destruction during freezing, a method of applying a high voltage electric field to the antifreeze is described.

JP-A-11-101536 JP 2002-277118 A JP 2002-350016 A JP 2001-292553 A

  When storing seafood and the like with acidic electrolyzed water ice as described above, it is preferable that the acidic electrolyzed water ice is as difficult to melt as possible in order to safely store the seafood and the like over a long period of time. However, the acidic electrolyzed water ice made by the conventional brine refrigeration method and air blast refrigeration method has a characteristic that the ice structure is weak and easily broken because the brine temperature or the freezing room temperature is -15 to -25 ° C. Thaws relatively quickly. For this reason, when a long transport time is required, such as when transporting seafood, etc. to a long distance, or when the display time until the product is sold to consumers is long, cold storage is insufficient and the sterilizing power is reduced. There was a risk that safe storage could not be obtained.

  In addition, when acid electrolyzed water is frozen to obtain acid electrolyzed water ice, generally, ice formation begins to freeze from pure water in the solution, and impurities are frozen later. If included, it will take a long time to freeze completely. Even in ice making of acidic electrolyzed water by the conventional brine refrigeration method or air blast refrigeration method, there is a problem that ice making efficiency is lowered due to the influence of mineral components, water supercooling phenomenon, and the like, resulting in a longer ice making time. For this reason, it was necessary to expand and enlarge the size of equipment to produce a large amount of ice.

  In Patent Document 4, as described above, in order to delay the freezing of moisture in the tissue of the frozen food and prevent tissue destruction, when the frozen food is frozen, a high voltage electric field is applied to the brine solution to generate maximum ice crystals. It is described that the time for passing the belt (-1 to -5 ° C) is shortened. However, it is not described that when a high-voltage electric field is applied during ice making of acidic electrolyzed water, acidic electrolyzed water ice that is suitable for storage of fish and shellfish and the like and that can be obtained in a short time can be obtained. Although the electric field is applied, the purpose is completely different.

  The present invention has been made in view of the above problems, and an object of the present invention is to efficiently produce acidic electrolyzed water ice that is difficult to thaw and lasts long, and to provide a method for preserving seafood and the like with this acidic electrolyzed water ice. To do.

In order to solve the above-mentioned problems, the present inventors have studied about ice making of acidic electrolyzed water ice that is difficult to thaw and lasts long. As a result, a high voltage electric field is applied to the acid electrolyzed water obtained by electrolyzing the salt water to produce ice. As a result, acidic electrolyzed water ice with a strong freezing structure is obtained, the acidic electrolyzed water ice is strong and difficult to thaw and lasts long, and thus by applying a high voltage electric field to the acidic electrolyzed water, The present inventors have found that ice can be made and have completed the present invention. That is, the present invention provides the following method for maintaining freshness of fish and shellfish.
(1) It is characterized by preserving seafood and the like using acidic electrolyzed water ice produced by applying a high-voltage electric field to acidic electrolyzed water obtained by electrolyzing an aqueous solution of deep ocean water, seawater or salt. A method for maintaining the freshness of seafood.
(2) The method for maintaining freshness of fish and shellfishes according to (1) above, wherein the acidic electrolyzed water is acidic water obtained by electrolyzing deep ocean water.
(3) The method for maintaining freshness of fish and shellfishes according to (1) or (2) above, wherein the pH of the acidic electrolyzed water is 2.5 to 6.5.
(4) The method for maintaining freshness of seafood or the like according to (1), (2) or (3), wherein a high voltage electric field of 5 to 100 kv is applied to the acidic electrolyzed water.
(5) The method for maintaining freshness of fish and shellfishes according to any one of (1) to (4), wherein the chlorine concentration of the acidic electrolyzed water is 20 to 200 ppm.

  According to the present invention, it is possible to produce acidic electrolyzed water ice with a strong freezing structure in a short time by applying a high-voltage electric field to acidic electrolyzed water obtained by electrolyzing a saline solution to produce ice. Therefore, when seafood and the like are stored in this acidic electrolyzed water ice, the ice lasts long, so that the seafood and the like can be kept cold for a long time and the freshness thereof can be maintained.

  In addition, when deep sea water is used as saline, it is clean saline that does not contain bacteria, so it can be used as it is as raw water for electrolysis, and acidic electrolyzed water obtained from this raw water Acidic electrolyzed water ice with a high chlorine concentration and high bactericidal power can be obtained, so that the acidic electrolyzed water ice is suitable for preservation of seafood and the like, and particularly effective for preservation of seafood and the like in the ocean. is there.

  In the present invention, seafood and the like are stored using acidic electrolyzed water ice that has been made by applying a high-voltage electric field to acidic electrolyzed water. This acidic electrolyzed water ice can be obtained by making acidic electrolyzed water obtained by electrolyzing water for electrolysis (hereinafter also abbreviated as “electrolysis”). The electrolysis of the electrolyzing water is substantially the same as the conventional salt electrolysis practiced in the industry, and therefore detailed description thereof is omitted.

  As water for electrolysis used in the present invention, deep sea water, seawater or an aqueous solution in which salt is dissolved can be used as appropriate, but deep sea water or seawater containing a large amount of mineral components other than sodium chloride is preferable. In particular, for example, deep sea water collected from deep seas of 200m or deeper, for example, 1) Since there are many mineral components and there are few bacteria etc., it can be electrolyzed without sterilization treatment. 2) High concentration electrolyte (NaCl) Therefore, it can be electrolyzed in a relatively short period of time. 3) Since the concentration of the electrolyte is high, effective chlorine is dissolved at a relatively high concentration. Ordinary seawater is easy to collect, but generally there is a high possibility that bacteria and the like exist, so electrolysis after sterilization is required. In the case of deep ocean water or seawater, when the salinity is too high, for example, electrolysis can be performed after performing a salt reduction treatment using an electrodialysis method or after diluting with tap water. Furthermore, although the acidic electrolyzed water is usually made as it is, it may be adjusted with alkaline electrolyzed water or tap water if necessary, or may be made by adding a functional component such as a fragrance.

  In the present invention, acidic electrolyzed water obtained by electrolyzing water for electrolysis is preferably in the range of pH 2.5 to 6.5, more preferably in the range of pH 4.5 to 5.5. If pH is the said range, when ice-making and fish and shellfish etc. are kept cold, desired bactericidal power will be acquired and it will not be necessary to attack fish and shellfish. That is, when the pH is 6.5 or more, the sterilizing power is reduced, and there is a possibility that the sterilization of the bacteria adhering to the seafood and the like cannot be sufficiently obtained. On the other hand, when the pH is less than 2.5, the sterilizing power is increased, but when the ice melts and comes into contact with the surface of fish and shellfish, the fish and shellfish may be damaged by a strong acidic solution, which is not preferable.

  Moreover, as an effective chlorine concentration (DCl) of acidic electrolyzed water, the range of 20-200 ppm is preferable, and the range of 40-100 ppm is more preferable. Chlorine has a bactericidal action, so it has a high possibility of showing a useful effect for preservation of fresh fish and the like, but at the same time, there is a possibility that the freshness of the fish is deteriorated by an oxidizing action. If DCl is less than 20 ppm, sufficient bactericidal action cannot be obtained, and if it exceeds 200 ppm, the oxidative action becomes stronger and the freshness of the fish may be deteriorated.

  In the present invention, ice making technology generally used for mass production of ice can be used as basic ice making technology. Specifically, a brine freezing method in which a container containing acidic electrolyzed water is immersed in a refrigerant (brine liquid) having a low freezing temperature in a freezing tank and frozen, and for example, the acidic electrolyzed water stored in the container is stored in a freezer. An air blast freezing method in which the inside is rapidly cooled with air and frozen can be exemplified. When the brine refrigeration method and the air blast refrigeration method are compared, the thermal conductivity of the brine liquid is larger than that of air, and therefore the former has the advantage that the freezing rate can be faster than the latter. In these methods, the brine solution or air is cooled to a predetermined temperature by a refrigerator or the like. Since the ice making temperature (ice making speed) is substantially determined by the refrigerant temperature, the refrigerant temperature is selected in consideration of the ice making speed and the like. As the refrigerant temperature, a range of −10 to −60 ° C. is usually preferable, and a range of −25 to −38 ° C. is more preferable in view of equipment cost and ice making efficiency.

  The present invention is characterized in that a high voltage electric field is applied to the acidic electrolyzed water when ice is produced by the above refrigerating method. As a means for generating a high voltage electric field, for example, a high electric field generator such as a high-frequency potential generator (Japanese Patent Publication No. 38-6106) is suitable. In order to apply a high electric field to the acidic electrolyzed water to be iced, one of the secondary terminals of the transformer of the high electric field generator is insulated and the other is supplied with a high voltage electric field in the acidic electrolyzed water in the freezer or freezer. Connect to the ice making machine so that it can be applied. The strength of the voltage to be applied varies depending on the amount of acidic electrolyzed water to be iced and is not specified, but is usually preferably in the range of 5 to 100 kv, more preferably in the range of 10 to 45 kv. If it is the voltage of this range, acidic electrolyzed water can be frozen into a strong freezing structure quickly.

  Next, an outline of an ice making device using a brine refrigeration method and an air blast refrigeration method will be described with reference to the drawings. FIG. 1 is a schematic front view of an ice making device according to a preferred embodiment of the brine refrigeration method, partly in cross section. The ice making apparatus includes a freezer tank 1, a refrigerator 7, and a high electric field generator 8. The freezer tank 1 is a heat insulating structure made of, for example, stainless steel (SUS304, the same applies hereinafter), and contains a brine solution therein. The upper part of the freezing tank 1 is open, and the ice making frame 2 carrying or supporting a plurality of ice making tubes 3 containing the acid electrolyzed water to be iced is lowered and inserted into the freezing tank 1 through the opening. The ice making tube 3 can be immersed in the brine solution. The ice making frame 2 is supported by a mounting base 4. The ice making pipe 3 is moved up and down along the two guides 10 provided on both sides of the freezing tank 1 by, for example, a drive motor (not shown). The ice making frame 2 carrying or supporting can be taken in and out of the freezing tank 1. This structure is substantially the same as a normal brine refrigerating apparatus, and a widely used ice making apparatus can be used.

  In the present ice making apparatus, the ice making tube 3 is a container for containing acidic electrolyzed water to be iced. The upper part is open, the acidic electrolyzed water to be iced is injected from the opening, and the produced acidic electrolyzed water ice is taken out. On the other hand, the ice making frame 2 is a frame for supporting the ice making tube 3 when immersed in the brine solution of the freezing tank 1, and has a structure that can be supported by hooking the ice making tube at the top or placing it on the bottom. In addition, when placed in the freezer tank 1, the brine solution uniformly contacts the outer surface of the ice making tube 3 so that the ice making tube 3 can be uniformly cooled so that the entire ice making tube 3 has a mesh shape or a lattice shape. Although not shown, the ice making frame 2 can be provided with a lid as required.

  As a material of the ice making tube 3 and the ice making frame 2, stainless steel having a desired strength and excellent in acid resistance and rust prevention is preferable. However, it is not limited to this. For example, the ice making tube 3 can be formed of a plastic such as high-density polyethylene having low temperature resistance and acid resistance. Since the acidic electrolyzed water is made in the ice making tube 3, the shape (shape and size) of the ice to be made is determined by the shape of the ice making tube 3. Therefore, the shape of the ice making tube 3 to be used may be appropriately determined according to the shape of the ice to be produced. Normally, plate-shaped or square-shaped ice is often made using a rectangular ice-making tube with an open top, but a cylindrical tube with a bottom is used for columnar ice. Furthermore, by changing the shape of the ice-making tube, the ice-making method, the ice-making conditions, etc., it is possible to obtain ice in a square shape, a plate shape, a flake shape or a sherbet shape.

  The height of the ice making tube 3 is the same as or smaller than the height of the ice making frame 2 when the ice making tube is supported on the top of the ice making frame 2, and the ice making tube 3 is placed on the bottom of the ice making frame 2. It is preferable that the height of the ice making frame 2 is the same as or slightly larger than that of the ice making frame 2. When the ice making tube 3 is supported by the ice making frame 2, it is preferably arranged in parallel with a predetermined interval between adjacent ice making tubes so that the brine solution can freely flow between the ice making tubes. . Further, when the ice making tube is made into a split type or tapered toward the bottom, it is possible to easily take out the ice made from the ice making tube.

  The freezing tank 1 is generally provided with stirring means 5 for stirring or circulating the brine solution in the freezing tank. By stirring the brine solution in the freezing tank with this stirring means and making the temperature of the brine solution uniform, the ice making tube containing the acidic electrolyzed water can be uniformly and efficiently cooled with the brine solution. At the same time, the brine solution also makes good contact with the heat exchange unit 6 of the refrigerator 7, so that the brine solution can be efficiently cooled by the refrigerator 7.

  As the brine solution, an aqueous calcium chloride solution, propylene glycol, alcohol solution, or the like having a freezing temperature lower than the ice making temperature can be used, and these can also be used in combination. Among these, an alcohol solution is particularly preferable in that it is easy to obtain a low temperature and is inexpensive.

  In this ice making device, a high voltage electric field is applied from the high electric field generator 8 to the acidic electrolyzed water that is made in the freezing tank 1. One of the secondary terminals of the high electric field generator 8 is insulated, and the other output end is connected to the conductor 9 so as to be in contact with the freezing tank 1. In this example, the terminal on the non-insulating side of the high electric field generator 8 is connected to the freezing tank 1 in this way. However, the terminal can be connected to an ice making frame or an ice making tube or the like. You may connect. If the freezer 1, the ice making frame 2 and the ice making tube 3 are made of stainless steel, these can be conducted through a brine solution or to each other to finally apply a high voltage electric field to the acidic electrolyzed water in the ice making tube. The high voltage electric field applied to the freezing tank 1 as in this apparatus is transmitted to the ice making pipe directly or via an ice making frame by conduction, and is given to the acidic electrolyzed water in the ice making pipe. In addition, when a high voltage electric field is applied to the ice making frame, the high voltage electric field can be applied to the acidic electrolyzed water similarly from the ice making frame to the ice making tube. In this case, the closer the position to which the high voltage electric field is applied is to the acidic electrolyzed water, the greater the effect of the high voltage electric field on the acidic electrolyzed water. In addition, the freezing tank 1 is installed and insulated with the electric insulating material 12 interposed in the floor 11 so that only an electric potential may be applied without passing an electric current through acidic electrolyzed water.

  The acidic electrolyzed water can be made by applying a high voltage electric field by the following method using the ice making apparatus. In a state where the ice making frame 2 is raised, acidic electrolyzed water is poured into the ice making tube 3, and the ice making tube 3 is supported by the ice making frame 2. Separately, the brine solution in the freezer is cooled to a predetermined temperature by the refrigerator 7 while being stirred by the stirring means 5, and a high voltage electric field is applied to the freezer 1 by turning on the high electric field generator 8. Apply. Next, the ice making frame 2 is lowered and charged into the freezing tank through the upper opening, and the ice making tube 3 containing the acidic electrolyzed water is immersed in the brine solution. In this state, by cooling the acidic electrolyzed water in the ice making tube with a brine solution for a certain period of time, the acidic electrolyzed water can be frozen while applying a high voltage electric field to obtain acidic electrolyzed water ice. The iced acidic electrolyzed water ice is taken out from the ice making tube by raising the ice making frame, and is stored in an appropriate manner for use.

  Next, ice making by the air blast freezing method will be described. In the case of the air blast freezing method, the ice making principle is substantially the same as that of the conventional method except that the acidic electrolyzed water is frozen while applying a high voltage electric field. Therefore, the illustration and description regarding this will be omitted, and the point of applying a high-voltage electric field to the acidic electrolyzed water will be outlined with reference to the drawings. FIG. 2 shows an ice making shelf 13 (corresponding to the ice making frame in FIG. 1) for supporting an ice making tube containing acidic electrolyzed water and accommodating it in a freezer. Shows the connected state. As shown in the figure, the ice making shelf 13 in this example has three stages of stainless steel net shelves, and is configured such that, for example, stainless steel ice making tubes containing acidic electrolyzed water can be arranged in parallel on the net shelf. However, the ice making shelf may have a structure in which an ice making tube is suspended or placed on the bottom and supported in the same manner as the ice making frame of the brine refrigerating method.

  An electrical insulating material 12 is provided at the bottom of the ice making frame so that the ice making shelf 13 can be installed in a freezer. And in order to apply a high voltage electric field to the acidic electrolyzed water frozen in the freezer, one of the secondary side terminals of the high electric field generator 8 is connected to a part of the ice making shelf 13 by the conducting wire 15 as described above. ing. The high voltage electric field applied to the freezer shelf 13 gives an electric field to the acidic electrolyzed water in the ice making tube.

When a high voltage electric field is applied to acidic electrolyzed water by the method of the present invention, acidic electrolyzed water ice having a tenacious strength that is difficult to thaw and lasts long can be obtained in a short time. Although the reason is not clear, when a high voltage electric field is applied to the acidic electrolyzed water during ice making, solidification nuclei are generated due to the influence of water dissociation and the movement of H ⁺ and OH ⁻ , and the acidic electrolysis containing minerals It is presumed that water is easily frozen and the crystal structure of the frozen acidic electrolyzed water ice is strengthened. Moreover, the addition of a high voltage electric field affects the solidification of the supercooled water to the acidic electrolyzed water, thereby shortening the ice making time. It is possible to freeze acid electrolytic water ice in a short time by freezing relatively quickly.

  The seafood and the like to be preserved in the present invention include marine products such as fish, shellfish and crustaceans, marine products, livestock products such as meat that can be preserved with ice, and processed products thereof. In particular, marine products represented by fish are suitable for ice storage, and further, it is easy to use the effect of preventing the proliferation of sterilization by keeping the acidic electrolyzed water ice cold and the sterilizing effect of the acidic electrolyzed water when the ice melts. Preferred.

  In the present invention, seafood and the like can be cooled and stored in the same manner as ice storage so far using iced acidic electrolyzed water ice. In this case, the acidic electrolyzed water ice can be crushed to an appropriate size and mixed with tap water ice if necessary.

(Example 1)
The following two methods were used to verify whether acidic electrolyzed water obtained by electrolyzing deep sea water (hereinafter referred to as deep water) can be effectively used for maintaining the freshness of fish.
(1) As an index for maintaining the freshness of fish, the effects of electrochemically treated deep water on cells are examined by examining the concentration of peroxide and the number of bacterial growth.
(2) Process acid electrolyzed water into ice and verify whether it can be used to maintain the freshness of fish.
1. Water used The water used for the experiment is as follows.
Raw deep-sea water: untreated deep-water acidic electrolyzed water without electrolytic treatment: constant-current electrolysis (0.8A), electrolysis using a two-tank reservoir type electrolyzed water generator (Altech) 1. Strong acidic water tap water obtained on the anode side when electrolyzed for 10 minutes: Untreated tap water not subjected to electrolytic treatment Sample fish A salmon (length: about 25 cm) caught in the sea was used as an experiment target. The fish was purchased commercially, and samples were prepared from those that had been refrigerated and stored for experiments.
3. Measurement of physical and chemical properties of water used The physical and chemical properties of each water used were measured using the following equipment and methods.
The pH is a pH meter (F22) manufactured by HORIBA, Ltd., the conductivity (EC) is a Castany ACT conductivity meter manufactured by HORIBA, and the dissolved oxygen amount (DO) is a 5100 type dissolved oxygen meter manufactured by YSI, redox potential. (ORP) is an oxidation-reduction potentiometer (93001-10D) manufactured by Horiba, Ltd., the analysis of effective chlorine concentration (DCl) is Nissan Aqua Check FW (trade name) manufactured by Nissan Chemical Industries, and the analysis of minerals is Lehman Labs Measurements were made using plasma emission spectrometers manufactured by LEEMAN LABS, INC. The results are shown in Table 1.

深層水は高濃度の電解質（NaCl）を含んでいるので、比較的短時間で電解処理ができた。酸性電解水の場合、表１から明らかのように有効塩素を比較的高濃度で溶存しており、塩素には殺菌作用があるので、鮮魚の保存に有効である可能性が高い。しかし、この塩素の酸化作用によって魚の鮮度を劣化させる可能性も残されている。
４．過酸化物の測定
強酸性の酸性電解水が魚の酸化劣化を増強する可能性があるため、魚の過酸化物（POV）値をＴＢＡ法で測定することによって、酸化劣化に及ぼす影響を調べた。ここで、ＴＢＡ法は魚のすり身にリン酸緩衝液を入れて更に細かくし、これに酢酸緩衝液、抗酸化物質、界面活性剤等を加えて加熱し、冷却後に酢酸エチルを加え、遠心分離した後に吸光度測定（５３２ｎｍ）するもので、ＴＢＡ値はその測定値である。また、酸性電解水を持続的に作用させる目的で氷を作成し、魚を氷冷して保存し、酸化劣化がどのように進むかを調べた。
実験方法は、酸性電解水等の使用水を製氷庫で製氷し、図３に示すように発泡スチロール箱１５に１匹の鰯１６を入れその上から氷１７を被せるように敷き詰めし、２４時間後に取りだしてその酸化劣化をＴＢＡ法にて測定し、使用水（氷）による酸化劣化を比較した。使用した氷の種類は、表１の使用水を凍結して得られる酸性電解水氷、水道水氷および深層水原水氷の３種類である。図４は３種類の氷で氷冷した魚のＴＢＡ値を示したものである。図４から明らかのように、水道水氷および深層水原水氷による魚のＴＢＡ値は２倍以上に上昇しているのに対し、酸性電解水氷では酸化が５０％程度抑制されている。このことから、酸性電解水氷の方が他の氷より魚の酸化劣化を抑制できることが分かる。
５．酸性電解水氷による抗菌作用
図５のような装置を用いて、酸性電解水の抗菌作用を調べた。菌の増殖を確認する方法として、魚の表面の細菌数と魚から溶け出してくる水溶液中の細菌数を測定した。いずれの実験も魚に直接氷が接触しないように、図５に示す如く発泡スチロール容器１８にスノコ１９を敷き、その上に鰯（５匹）１６を入れて上からポリエチレンシート２０を被せ、シートの上に次の３種類の裂氷を被せて蓋をする。規定時間経過ごとに魚の体表面の細菌数と保存中に溶け出して容器底部２１に溜まる水中の細菌数とを測定した。図６は酸性電解水氷と深層水氷で冷却した場合における、魚の表面における細菌数の経時変化を示し、図７は酸性電解水氷、深層水氷、純水氷で冷却した場合における、魚から溶け出した水中の細菌数の経時変化を示す。
（使用した氷の種類）
（ａ）酸性電解水氷：２０ｍＭのＮａＣｌ水溶液を電解して得られる酸性電解水の氷
（ｂ）深層水氷：無処理の深層水原水（表１参照）の氷
（ｃ）純水氷 ：精製水氷
なお、細菌の測定は、拭き取り検査法キット（川本産業株式会社製の滅菌綿棒（電子線滅菌済み））を使って細菌の培養をおこない、細菌の増殖率を指標として抗菌作用の評価を行った。その拭き取り検査法の手順は次の通りである。
１）滅菌した綿棒を１０ｍｌの滅菌水に浸し、圧搾後、検体魚体表面の拭き取りを行う。２）魚体表面の拭き取り後、滅菌水に綿棒を戻し、綿棒についた検体を溶解させる。
３）寒天培地のシャーレに検体を含む溶液（１ｍｌ）を分け、インキュベータ（３５℃）で培養する。
４）培養は検体希釈１０倍および１００倍で行う。
５）培養後、光学顕微鏡下でコロニーの数を調べる。

Deep water contains a high concentration of electrolyte (NaCl). In the case of acidic electrolyzed water, as shown in Table 1, effective chlorine is dissolved at a relatively high concentration, and since chlorine has a bactericidal action, there is a high possibility that it is effective for preservation of fresh fish. However, there is still a possibility that the freshness of fish is deteriorated by the oxidizing action of chlorine.
4). Measurement of Peroxide Since strongly acidic acidic electrolyzed water may enhance the oxidative degradation of fish, the influence on oxidative degradation was investigated by measuring the peroxide (POV) value of fish by the TBA method. Here, the TBA method is further refined by adding a phosphate buffer to fish surimi, adding acetate buffer, antioxidant, surfactant, etc. to this, heating, cooling, adding ethyl acetate, and centrifuging. The absorbance is measured later (532 nm), and the TBA value is the measured value. In addition, ice was prepared for the purpose of sustaining acidic electrolyzed water, and the fish was stored in an ice-cooled state to investigate how oxidative degradation progressed.
In the experiment method, water used such as acidic electrolyzed water is made in an ice maker, and as shown in FIG. 3, one bottle 16 is placed in a foamed polystyrene box 15 and covered with ice 17 from above, and 24 hours later. The oxidative deterioration was measured by the TBA method, and the oxidative deterioration due to water used (ice) was compared. There are three types of ice used: acidic electrolyzed water ice obtained by freezing the water used in Table 1, tap water ice, and deep water source water ice. FIG. 4 shows the TBA values of fish cooled with three types of ice. As is clear from FIG. 4, the TBA value of fish by tap water ice and deep water source water ice has increased more than twice, whereas in acid electrolyzed water ice, oxidation is suppressed by about 50%. This shows that acidic electrolyzed water ice can suppress oxidative degradation of fish more than other ice.
5). Antibacterial Action by Acid Electrolyzed Water Ice The antibacterial action of acidic electrolyzed water was examined using an apparatus as shown in FIG. As a method for confirming the growth of the bacteria, the number of bacteria on the surface of the fish and the number of bacteria in the aqueous solution dissolved from the fish were measured. In both experiments, in order to prevent the ice from coming into direct contact with the fish, a slat 19 was laid on the polystyrene foam container 18 as shown in FIG. 5, and a cocoon (5 animals) 16 was placed on it, and a polyethylene sheet 20 was covered from above. Cover with the following three types of icy ice. The number of bacteria on the surface of the fish body and the number of bacteria in the water that dissolved during storage and accumulated in the container bottom 21 were measured at each specified time. FIG. 6 shows changes over time in the number of bacteria on the surface of fish when cooled with acidic electrolyzed water ice and deep water ice, and FIG. 7 shows fish when cooled with acidic electrolyzed water ice, deep water ice, and pure water ice. Shows the time course of the number of bacteria dissolved in water.
(Type of ice used)
(A) Acid electrolyzed water ice: Acid electrolyzed water ice obtained by electrolyzing a 20 mM NaCl aqueous solution (b) Deep water ice: Untreated deep water raw water (see Table 1) (c) Pure water ice: Purified water ice Bacteria are measured using a wiping test kit (sterilized cotton swab (sterilized by electron beam) manufactured by Kawamoto Sangyo Co., Ltd.), and the antibacterial activity is evaluated using the bacterial growth rate as an index. Went. The procedure of the wiping inspection method is as follows.
1) Immerse the sterilized cotton swab in 10 ml of sterilized water, and after squeezing, wipe the surface of the specimen fish body. 2) After wiping the fish surface, return the swab to sterilized water and dissolve the sample on the swab.
3) Divide the solution (1 ml) containing the specimen into a petri dish of agar medium and culture in an incubator (35 ° C.).
4) Culture is performed at 10 and 100 times sample dilution.
5) After culture, examine the number of colonies under an optical microscope.

  As apparent from FIG. 6, the growth of bacteria on the surface of the fish body decreased from the initial value of 3000 to about 500 in the acidic electrolyzed water ice, and in particular, after 3 hours, the bactericidal effect is greater than in the deep water ice. Further, it can be seen from FIG. 7 that the growth of bacteria is suppressed when the acidic electrolyzed water ice comes into contact with the solution dissolved and dissolved from the fish. The acid electrolyzed water in which the acid electrolyzed ice is dissolved suppresses the growth of bacteria by 100%, and the inhibitory effect is superior to other ice.

  This is because there is a lot of effective chlorine that shows bactericidal power in acidic electrolyzed water, and it vaporizes in the process of dissolving acidic electrolyzed water ice, and its gas component indirectly sterilizes bacteria on the fish body surface. it is conceivable that. Furthermore, since strongly acidic electrolyzed water dissolved during frozen storage exhibits a strong sterilizing power, acidic electrolyzed water ice is suitable for storing fish and shellfish that are prone to bacteria.

(Example 2)
When acidic electrolyzed water and pure water (milliQ) obtained by electrolyzing deep seawater are subjected to a brine refrigeration method and an air blast refrigeration method, with or without a high-voltage electric field applied to the acidic electrolyzed water during ice making Ice making was performed separately, and each ice making time was measured, and the breaking strength of each ice piece was measured by the following method.

(1) Ice making water The pure water used for ice making is pure water with ultrapure water production equipment (Nihon Millipore), and the acidic electrolyzed water is pure water with the characteristics shown in Table 2 using a portable superoxide water generator (Altech). Water and acidic electrolyzed water were prepared.

(2) Ice making apparatus A. Brine refrigeration unit: Re-Joyce Quick Freezing System RQF-10
(Alpha system)
Brine solution: Alcohol (initial concentration 67.9%, operating concentration 55%)
Brine capacity: 180 liters Refrigerator: Hitachi Scroll 22 (KX-3A2)
Compressor output: 2.2kW
Refrigerant gas: R-22
Brine temperature: -35 ° C
Additional voltage: Alpha electric field high potential generator (additional 18kV, non-additional switching type)
B. Air blast freezer: Pre-chamber freezer Freezer: Sanyo LCU-N100P
Compressor output: 7.5kW
Refrigerant gas: R-22
Freezer temperature: -35 ° C
Additional voltage: Alpha electric field high potential generator (additional 18kV, non-additional switching type)

(3) Ice making method A polyethylene bag was inserted into a stainless steel ice making tube (W62 × D15 × H150 mm), and 110 cc of ice making water was put into this bag to make ice by the following method. The ice making water in the polyethylene bag is frozen in the shape of an ice making tube.
A. Brine refrigeration 1) Set the ice making tube on the ice making frame.
2) Turn on the high-field potential generator switch when voltage is applied, and turn it off when no voltage is applied.
3) Open the lid of the freezing tank of the refrigeration unit and immerse the ice making frame in the brine solution in the cooling tank.
4) Close the freezer tank lid and freeze.
B. Air blast refrigeration 1) Switch on the electric field potential generator.
2) In the case of voltage application, place the ice-making tube in a metal ice-making frame in the freezer, and in the case of no voltage application, lay wooden slats in the freezer and place the ice-making tube on it.
3) Close the freezer door and freeze.

(4) Ice breaking strength test The breaking strength of each ice piece made by changing the freezing method and ice making conditions was measured using a texture analyzer TA-Hdi (manufactured by Eiko Seiki Co., Ltd.). In this measuring method, as shown in FIG. 8, a sample ice 25 of a predetermined size is set on a measuring table 23 of a measuring instrument 22, and the central part of the sample ice is pressed from above with a specified push blade 24 so that the ice is completely formed. It measures the pressing force when the ice breaks and the distance (pressing distance) that it moves from when the pressing blade 24 contacts the ice until it breaks. The sample ice is a rectangular parallelepiped having a width of 62 mm, a length of 150 mm, and a thickness of 15 mm. The push blade 24 is made of a metal plate having a thickness of 2 mm and a width of 69.5 mm, and its lower tip has a cutting edge of 70 degrees. Yes. FIG. 9 shows the measurement unit. The measuring table 23 is provided with a pair of fixed guides 26 having a length of 90 mm and a height of 30 mm with an interval of 62 mm. The pair of fixed guides 26 has a pressing blade guide 27 at an intermediate position in the length direction. They are formed to face each other. The sample ice 25 is set between the fixed guides 26, the pressing blades 24 are inserted into the pressing blade guides 27 of the fixed guides 26, and lowered along the pressing blade guides.

  The measurement was performed four times for each type of ice, and the average value of the pressing force when the ice broke was determined as the simple strength. Table 3 shows the measurement results of this simple strength. Table 4 shows the correlation between the simple strength of each ice and the pressing distance, and it can be judged that the arrangement of water molecules in each ice is higher as the pressing distance is shorter even if the simple strength is the same. In Table 4, the pressing distance is an average of four measurement values.

表３および表４から明らかのように高電圧電場を付与して製氷した酸性電解水氷は、電場を付与しないで製氷した酸性電解水氷に比べて固い粘りのある氷となる。エアブラスト冷凍法では、３種類の水の容器を同時に冷凍室内に設置し、１７０分で−３１〜−３３℃の酸性電解水氷を作った。この場合−３１℃に到達する時間が、純水１５５分、電場なし酸性電解水１６５分、電場有り酸性電解水１０５分であり、電場有り酸性電解水はその後６５分間で−３３℃まで氷温度が低下した。その結果、電場有り酸性電解水氷の平均押圧力は電場なし酸性電解水氷とほぼ同等の強度であるが、押圧距離が３種類の氷の中で一番短くなり、すなわちＦ／Ｄ値が一番大きくなり、固い氷であるといえる。

As is apparent from Tables 3 and 4, acidic electrolyzed water ice made by applying a high-voltage electric field becomes harder and more viscous ice than acidic electrolyzed water ice made without applying an electric field. In the air blast freezing method, three types of water containers were installed in the freezing chamber at the same time, and acid electrolyzed water ice of −31 to −33 ° C. was produced in 170 minutes. In this case, the time to reach −31 ° C. is 155 minutes of pure water, 165 minutes of acidic electrolyzed water without electric field, and 105 minutes of acidic electrolyzed water with electric field. Decreased. As a result, the average pressing force of acidic electrolyzed water ice with an electric field is almost the same as that of acidic electrolyzed water ice without an electric field, but the pressing distance is the shortest of the three types of ice, that is, the F / D value is The largest and hardest ice.

  On the other hand, in the case of the brine refrigeration method, pure water without an electric field and acidic electrolyzed water were simultaneously immersed in a brine refrigeration tank and taken out after 13 minutes. Further, the acidic electrolyzed water with an electric field was taken out because it reached −32.8 ° C. after being soaked for 10 minutes. In this case, the time for the temperature of the three types of water to reach −31 ° C. was 13 minutes for pure water, 10 minutes for acidic electrolyzed water without an electric field, and 8 minutes for acidic electrolyzed water with an electric field. There is no difference in the average pressing force between acidic electrolyzed water ice with and without an electric field, but the time for cooling is 3 minutes shorter for acidic electrolyzed water ice with an electric field. The difference is in the pressing distance, and sticky ice was made despite the same hardness. In other words, if acidic electrolyzed water ice with an electric field is immersed in a brine freezing tank for 13 minutes in the same manner as other ices, it is expected that the pressing distance will be shortened and the F / D value will be increased due to increased hardness.

(5) Ice making time FIG. 10 shows the temperature change until pure water and acidic electrolyzed water are approximately balanced with the freezer temperature (−35 ° C.) in ice making by the air blast freezing method, and FIG. 11 shows ice making by the brine freezing method. , Each shows a temperature change until pure water and acidic electrolyzed water substantially equilibrate to the brine temperature (−35 ° C.). As is clear from FIG. 10, acidic electrolyzed water that does not give an electric field is more difficult to cool than pure water, and in the temperature range of about −5 ° C. or less, the acidic electrolyzed water becomes 10 minutes to 20 minutes later at the same temperature. ing. On the other hand, acidic electrolyzed water to which a high voltage electric field is applied is cooled to the same temperature about 60 minutes earlier than when no electric field is applied in the temperature range. From this, it can be seen that by applying a high-voltage electric field to acidic electrolyzed water that is difficult to cool, rapid cooling becomes possible and ice can be made in a short time.

  The brine refrigeration method is not as prominent as the air blast refrigeration method described above, but when a high-voltage electric field is applied to the acidic electrolyzed water, the cooling is accelerated with the passage of time, and ice can be made about 2 to 3 minutes faster than when no electric field is applied. . From these results, it was found that by applying a high voltage electric field to the acidic electrolyzed water, the cooling was significantly accelerated and the ice making time could be shortened.

  According to the present invention, seafood and the like are preserved with ice having a high bactericidal power by storing the seafood and the like with acidic electrolyzed water ice that has been made by applying a high voltage electric field, so that the freshness of the seafood is prolonged. Can hold. In particular, acidic electrolyzed water obtained by electrolyzing deep ocean water has a higher concentration of effective chlorine, so it has even better sterilizing power.Acid electrolyzed water ice obtained by making this acidic electrolyzed water is used for seafood in the ocean. It has a great practical effect in refrigerated storage of foods.

It is the front view which showed a part of brine refrigerating device which is preferable embodiment of this invention in the cross section. It is a perspective view of the ice making shelf frame and high potential generator of the air blast freezing device which are other embodiments of the present invention. It is a perspective view of the ice cold storage box for experiment of fish. It is a bar graph which shows the TBA value of a fish. It is sectional drawing of the ice storage box for experimental fish. It is a graph which shows the time-sterilization condition on the fish body surface according to the kind of ice. It is a graph which shows the time sterilization condition in melt | dissolution water according to the kind of ice. It is a front view of a texture analyzer. It is a perspective view of the sample ice fixing | fixed part of FIG. It is a graph which shows the ice making temperature change according to ice making water in the air blast freezing method. It is a graph which shows the ice making temperature change according to ice making water in a brine refrigerating method.

Explanation of symbols

1: Freezing tank 2: Ice making frame 3: Ice making tube 4: Mounting base 5: Stirring means 6: Heat exchanging unit 7: Refrigerator 8: High electric field generator 9: Conductor 11: Floor 12: Electrical insulating material 13: Ice making shelf frame

Claims (5)

  Fish and shellfish characterized by preserving seafood using acid electrolyzed water ice made by applying high-voltage electric field to acid electrolyzed water obtained by electrolyzing deep seawater, seawater or salt water How to keep freshness.   The method for maintaining freshness of seafood and the like according to claim 1, wherein the acidic electrolyzed water is acidic water obtained by electrolyzing deep ocean water.   The method for maintaining freshness of seafood or the like according to claim 1 or 2, wherein the acidic electrolyzed water has a pH of 2.5 to 6.5.   The method for maintaining freshness of seafood or the like according to claim 1, 2 or 3, wherein a high voltage electric field of 5 to 100 kv is applied to the acidic electrolyzed water. The method for maintaining freshness of fish and shellfishes according to any one of claims 1 to 4, wherein the acidic electrolyzed water has a chlorine concentration of 20 to 200 ppm.

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